Display system and information processing method

ABSTRACT

A display system includes: a video display apparatus; and a mobile terminal that communicate with each other. The video display apparatus includes: a measurement pattern generator that generates a plurality of measurement patterns; a projection unit that projects the measurement patterns; a first transceiver that communicates with the mobile terminal to receive information regarding distortion correction of video; and a distortion corrector that corrects the distortion. The mobile terminal includes: a camera unit that photographs the projected measurement patterns; a controller that generates the distortion correction information based on the photographed measurement patterns; and a second transceiver that communicates with the first transceiver to transmit the distortion correction information to the video display apparatus. The measurement pattern generator adds a common pattern to each measurement pattern, which indicates a reference position of each of the measurement patterns. The controller generates the distortion correction information based on the common pattern.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.16/092,009, filed Oct. 8, 2018, which claims the benefit ofPCT/JP2016/061752 filed Apr. 12, 2016 which are incorporated byreference as if fully set forth.

TECHNICAL FIELD

The present invention relates to a display system and an informationprocessing method, and particularly, the present invention relates to atechnique effective for distortion correction of a projection video.

BACKGROUND ART

A projector causes a video apparatus such as liquid crystal to transmitlight from a light source to provide an image on a desired screen or thelike. Thus, distortion may occur in the projected video in a case wherea direction of the light from the light source is caused to face thescreen.

For this reason, it is necessary that arrangement of the projector andthe screen is generally adjusted so as not to distort the projectedvideo when to install them. Alternatively, it is necessary to adjustdistortion of displayed video by using a distortion correcting functionor the like of the projector.

On the other hand, a technique called as projection mapping isattracting attention in recent years. In the projection mapping, videois projected to an object placed in the real world by using a videoprojecting apparatus such as a projector.

In the projection mapping, it is necessary to project video not only toa flat screen caused to face the projector, but also to a screen that isnot caused to face the projector and is placed with a predeterminedangle or an object with concavities and convexities.

As described above, in a case where a projection target such as a screenis not caused to face the projector, that is, in a case where an opticalaxis of the projector and a surface of the projection target cross atright angles with each other, geometric distortion occurs in theprojected video.

For example, in a case where a screen is installed so that an upper sideof the screen is near the projector and a lower side thereof is far fromthe projector and video with a square shape is projected from theprojector, so-called trapezoidal distortion occurs in which the video isprojected so that the upper side of the square is shorter than the lowerside thereof.

In fact, the similar phenomenon occurs not only in a vertical direction,but also in a horizontal direction. Thus, the video with a quadrangle,which is projected from the projector, is projected as a distortedsquare that does not have parallel sides.

In this case, by applying geometric correction of a reverse direction tovideo to be projected so as to counteract this distortion in advance, itbecomes possible to correctly display the video as a square. Thisgeometric correction, that is, the geometric conversion is called asperspective conversion or projective conversion, and can be realized bymatrix calculation. In order to calculate this matrix, it is necessaryto obtain information on a shape and a position of a projected object byany means.

One technique for realizing this is described in Japanese PatentApplication Publication No. 2013-192098 (see Patent Document 1), forexample. This Patent Document describes that: a marker becoming areference is projected from a projector; a shape of a projection targetis obtained by photographing the projection target by a camera of asmartphone; distortion is calculated from obtained video; and thedistortion is subjected to reverse correction.

RELATED ART DOCUMENTS Patent Documents

Patent document 1: Japanese Patent Application Publication No.2013-192098

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The technique of Patent Document 1 described above is that markers aredisplayed at four points on a screen. In this case, it is possible todetect and correct even distortion on the screen, for example,trapezoidal distortion that occurs due to a state that a projectionplane is not caused to face a projector. However, it is impossible todetect a shape of a projection plane with minute concavities and minuteconvexities, for example.

In order to detect the projection plane with minute concavities andminute convexities, it is necessary to project plural kinds ofcorrection video in which fineness of the markers is changed andphotograph the correction video each time by a camera. However, there isa problem that a shape of a projection plane cannot be obtainedcorrectly. This is because a position of correction video photographedby an unfixed camera such as one in a smartphone is changed whilephotographing multiple times due to influence of camera shake or thelike.

It is an object of the present invention to provide a technique capableof realizing distortion correction of a video more suitably.

The foregoing and other objects, and new features of the presentinvention will become more apparent from the detailed description of thepresent specification and the appending drawings.

Means for Solving the Problem

An outline of representative invention of the present inventiondisclosed in the present application will briefly be explained asfollows.

Namely, a representative display system includes a video displayapparatus, and a mobile terminal configured to communicate with thevideo display apparatus. The video display apparatus includes ameasurement pattern generator, a projection unit, a first transceiver,and a distortion corrector.

The measurement pattern generator is configured to generate a pluralityof measurement patterns. The projection unit is configured to projectthe plurality of measurement patterns generated by the measurementpattern generator. The first transceiver is configured to communicatewith the mobile terminal to receive information regarding distortioncorrection of video from the mobile terminal. The distortion correctoris configured to correct distortion of the video projected by theprojection unit on a basis of the information regarding the distortioncorrection of the video, which is received from the mobile terminal.

Further, the mobile terminal includes a camera unit, a controller, and asecond transceiver. The camera unit configured to photograph theplurality of measurement patterns projected by the projection unit. Thecontroller is configured to generate the information regarding thedistortion correction of the video on a basis of the plurality ofmeasurement patterns photographed by the camera unit. The secondtransceiver is configured to communicate with the first transceiver totransmit, to the video display apparatus, the information regarding thedistortion correction of the video, which is generated by thecontroller.

The measurement pattern generator is configured to add a common patternto each of the plurality of measurement patterns, the common patternindicating a reference position of each of the measurement patterns. Thecontroller is configured to generate the information regarding thedistortion correction of the video on a basis of the common patternadded to each of the plurality of measurement patterns.

In particular, a change in an imaging position of an image of each ofthe plurality of measurement patterns photographed by the camera unit iscompensated in the controller by using the common pattern added by themeasurement pattern generator.

Moreover, the mobile terminal includes a common pattern processor and adisplay. The common pattern processor is configured to generate a menuthat allows luminance, color, and a position of the common pattern to beselected therethrough. The display is configured to display the menugenerated by the common pattern processor.

The measurement pattern generator is configured to change the commonpattern in accordance with a selection result of the menu received bythe mobile terminal.

Effects of the Invention

Effects obtained by representative invention of the present inventiondisclosed in the present application will briefly be explained asfollows.

It is possible to realize correction of a video with high accuracy.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is an explanatory drawing showing one example of a configurationof a video display system according to a first embodiment;

FIG. 2 is an explanatory drawing showing one example of configurationsof a projector and a smartphone included in the video display systemshown in FIG. 1;

FIG. 3 is an explanatory drawing showing one example of stripe patternsthat are generated by a measurement pattern generator included in theprojector shown in FIG. 2;

FIG. 4 is an explanatory drawing showing another example of the stripepatterns that are generated by the measurement pattern generatorincluded in the projector shown in FIG. 2;

FIG. 5 is a flowchart showing one example of a setting process for adistortion correction coefficient to correct projection distortion bythe video display system shown in FIG. 2;

FIG. 6 is an explanatory drawing showing one example of correction of avideo reference position in a process at Step S204 in FIG. 5;

FIG. 7 is an explanatory drawing showing one example of a process atStep S205 in FIG. 5;

FIG. 8 is an explanatory drawing showing one example of a process ofdividing a correction region shown in FIG. 7;

FIG. 9 is an explanatory drawing showing one example of a common patternregion that is formed in a stripe pattern according to a secondembodiment;

FIG. 10 is a flowchart showing one example of a setting process for adistortion correction coefficient, which includes a switching processfor the common pattern region shown in FIG. 9;

FIG. 11 is an explanatory drawing showing one example of a commonpattern region formed in a stripe pattern according to a thirdembodiment; and

FIG. 12 is an explanatory drawing showing one example of screen displaywhen the common pattern region shown in FIG. 11 is switched.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In embodiments described below, the invention will be described in aplurality of sections or embodiments when required as a matter ofconvenience. However, these sections or embodiments are not irrelevantto each other unless otherwise stated, and the one relates to the entireor apart of the other as a modification example, details, or asupplementary explanation thereof.

Further, in the embodiments described below, in a case of referring tothe number of elements (including number of pieces, values, amount,range, and the like), the number of the elements is not limited to aspecific number unless otherwise stated or except the case where thenumber is apparently limited to a specific number in principle, and thenumber larger or smaller than the specified number may also beapplicable.

Moreover, in the embodiments described below, it goes without sayingthat the components (including element steps and the like) are notalways indispensable unless otherwise stated or except the case wherethe components are apparently indispensable in principle.

Similarly, in the embodiments described below, when the shape of thecomponents, positional relation thereof, and the like are mentioned, thesubstantially approximate and similar shapes and the like are includedtherein unless otherwise stated or except the case where it isconceivable that they are apparently excluded in principle. The samegoes for the numerical value and the range described above.

Further, the same components are in principle denoted by the samereference numeral throughout the drawings for describing theembodiments, and the repetitive description thereof will be omitted.

Hereinafter, the embodiments will be described in detail.

First Embodiment

<Configuration Example of Video Display Apparatus>

FIG. 1 is an explanatory drawing showing one example of a configurationof a video display system according to a first embodiment.

As shown in FIG. 1, the video display system includes a projector 101, asmartphone 102, and a screen 103. The projector 101 that is a videodisplay apparatus carries out video processing for inputted video toproject the video on the screen 103. Here, a light ray 105 shown bydotted lines of FIG. 1 indicates a direction of a light ray projected bythe projector 101.

The projector 101 and the smartphone 102 are allowed to communicate witheach other by means of a communication function by wireless, forexample. A communication technology between the projector 101 and thesmartphone 102 may be any wireless communication technology such asWi-Fi or Bluetooth.

<Configuration Example of Projector>

Next, configurations of the projector 101 and the smartphone 102 will bedescribed below.

FIG. 2 is an explanatory drawing showing one example of configurationsof the projector 101 and the smartphone 102 included in the videodisplay system shown in FIG. 1.

A configuration of the projector 101 will first be described. Theprojector 101 includes a video input unit 110, a video processor 111, adistortion corrector 112, an optical system 113, a microcomputer 114, amemory 115, a measurement pattern generator 116, and a wirelesstransceiver 117.

The video input unit 110 converts the inputted video outputted from apersonal computer or the like into an inner video format, for example.The inputted video is video with any of various kinds of video formatssuch as an HDMI (High-Definition Multimedia Interface) or a DisplayPort. Further, the inner video format is a general RGB (red, green, andblue), a YUV format, or the like, and it is not limited particularly.

An inner video signal processed by the video input unit 110 is inputtedinto the video processor 111. The video processor 111 executes videocorrection. As the video correction, there are contrast correction,color correction, and the like, for example.

The distortion corrector 112 carries out distortion correction and thelike of video in horizontal and vertical directions with respect to thevideo signal processed by the video processor 111. The video signal isthen converted into light and projected via the optical system 113. Thedistortion corrector 112 corrects distortion of the video by using adistortion correction coefficient (will be described later).

The optical system 113 that becomes a projection unit includes a lightsource. The optical system 113 converts the video signal into light bymeans of a video apparatus such as a liquid crystal, or DLP (DigitalLight Processing) and outputs the converted video signal. The methodthereof is not limited particularly.

Programs for controlling the whole projector 101 and the like are storedin the memory 115. The microcomputer 114 controls the projector 101 onthe basis of the program stored in the memory 115.

The measurement pattern generator 116 generates a stripe pattern that isa measurement pattern to measure a shape of a projection plane (will bedescribed later). The wireless transceiver 117 that is a firsttransceiver carries out wireless communication with a wirelesstransceiver 124 (will be described later) included in the smartphone102.

<Configuration Example of Smartphone>

Subsequently, a configuration of the smartphone 102 will be described.

The smartphone 102 includes a CPU 120, a memory 121, a camera 122, adisplay 123, and a wireless transceiver 124. The memory 121 storestherein programs, a distortion correcting application (will be describedlater), photograph data photographed by the camera 122, and the like.

The CPU 120 that functions as a controller and a common patternprocessor controls the entire smartphone 102 on the basis of theprograms stored in the memory 121. The camera 122 photographs video.

The wireless transceiver 124 that is a second transceiver carries outwireless communication with the wireless transceiver 117 of theprojector 101. The display 123 is a display, and is configured by aliquid crystal display, for example.

In this regard, with respect to a configuration of the smartphone 102,the smartphone 102 does not require a special configurationparticularly, and may be provided with the functions described above.Thus, the smartphone 102 is not limited to a smartphone, and may be aPersonal Digital Assistant (PDA) or the like that is illustrated by atablet terminal, for example.

<First Example of Stripe Pattern>

FIG. 3 is an explanatory drawing showing one example of stripe patternsthat are generated by the measurement pattern generator 116 included inthe projector 101 shown in FIG. 2.

First, stripe patterns a1 to a4 shown at a left side of FIG. 3 are shownas one example of the stripe patterns in a vertical direction.

The stripe pattern a1 shown at the upper left of FIG. 3 is formed by aregion 130 shown by a dotted line in FIG. 3. The entire video isdisplayed in the region 130 by white or high luminance. Hatching in theregion 130 indicates that the video is displayed by the white or highluminance. Hereinafter, in FIG. 3, hatching in each of regions indicatesthat video is displayed by white or high luminance.

Further, in the stripe pattern a2 shown under the stripe pattern a1, theentire video is formed by a region 132 shown by a dotted line and aregion 133 shown by a thick dotted line. The region 133 occupies righthalf of the video, and is white or high luminance. A white blank in theregion 132 occupies left half of the video. The region 132 that occupiesthe left half of the video indicates to be black or low luminance.Hereinafter, in FIG. 3, a white blank in each of regions indicates thatvideo is displayed by black or low luminance.

In the stripe pattern a3 shown under the stripe pattern a2, the entirevideo is formed by one region 132 shown by a dotted line and two regions133 each shown by a thick dotted line. The two regions 133 respectivelyformed at right and left ends of the video indicate to be white or highluminance, while the region 132 sandwiched by the right and left regions133 indicates to be black or low luminance.

In the stripe pattern a4 shown under the stripe pattern a3, the entirevideo is formed by two regions 132 each shown by a dotted line and threeregions 133 each shown by a thick dotted line. The regions 133positioned at right and left ends and a central portion of the videoindicate to be white or high luminance, while the region 132 sandwichedby the left and central regions 133 and the region 132 sandwiched by theright and central regions 133 indicate to be black or low luminance.

Subsequently, stripe patterns b1 to b4 shown at a right side of FIG. 3are formed by adding a common pattern region 131 to each of the stripepatterns a1 to a4 shown at the left side of FIG. 3. The common patternregion 131 that is a common pattern is a pattern indicating a peripheryof the entire video in each of the stripe patterns a1 to a4 shown at theleft side of FIG. 3, and is generated by the measurement patterngenerator 116.

A width of the common pattern region 131 is not limited particularly.However, the common pattern region 131 may have a width enough to bephotographed when projected video (will be described later) isphotographed by the camera 122 of FIG. 2. The common pattern region 131forms a common region in each of the stripe patterns a1 to a4. In otherwords, in the stripe patterns a1 to a4, an area of the common patternregion 131 is the same as each other.

Here, a video level of the common pattern region 131 is white or highluminance. All of the region 130, the region 133, and the common patternregion 131 are white or high luminance. However, the regions may havethe same luminance level, or a luminance level may be changed for theregions so long as the periphery of the entire video can be detected.

<Second Example of Stripe Pattern>

FIG. 4 is an explanatory drawing showing another example of the stripepatterns that are generated by the measurement pattern generator 116included in the projector 101 shown in FIG. 2. FIG. 4 shows one exampleof the stripe patterns in a horizontal direction, which are generated bythe measurement pattern generator 116.

In FIG. 4, in a stripe pattern f1 provided at the uppermost side, theentire video is formed by a region 130 that is white or high luminance.In a stripe pattern f2 shown under the stripe pattern f1, lower half ofthe video is formed by a region 133 that is white or high luminance, andupper half of the video is formed by a region 132 that is black or lowluminance.

In a stripe pattern f3 shown under the stripe pattern f2, upper andlower sides of the video are respectively formed by the regions 133 thatare white or high luminance, and a central portion of the video isformed by the region 132 that is black or low luminance.

Further, in each of these stripe patterns f1 to f3, a common patternregion 131 is formed at a periphery thereof as well as the stripepatterns b1 to b4 shown at the right side of FIG. 3.

<Example of Settings for Distortion Correction Coefficient>

Subsequently, an example of settings for a distortion correctioncoefficient to correct projection distortion will be described.

FIG. 5 is a flowchart showing one example of a setting process for thedistortion correction coefficient to correct the projection distortionby the video display system shown in FIG. 2.

In FIG. 5, the smartphone 102 detects distortion of video projected fromthe projector 101, calculates and sets a distortion correctioncoefficient. The CPU 120 executes these processes on the basis of thedistortion correcting application, which is an application stored in thememory 121 shown in FIG. 2.

An operator first connects the projector 101 to the smartphone 102 bymeans of wireless communication in advance. This wireless communicationis realized as wireless connection by the wireless transceiver 117 ofthe projector 101 and the wireless transceiver 124 of the smartphone102.

The operator then starts the distortion correcting application installedin the smartphone 102, and presses a start button for distortioncorrection in a state where the operator holds the smartphone 102 sothat video projected by the projector 101 falls in a photographing rangeof the camera 122, which is displayed on the display 123. As describedabove, it becomes a state where distortion correction start isinstructed.

Hereinafter, explanation will be made along a flowchart shown in FIG. 5.

When start of the distortion correction described above is instructed bythe smartphone 102, a generating instruction for a measurement patternis transmitted from the CPU 120 of the smartphone 102 to themicrocomputer 114 of the projector 101. This generating instruction istransmitted from the wireless transceiver 124 of the smartphone 102 viathe wireless transceiver 117 of the projector 101.

The microcomputer 114 that received this generating instruction causesthe measurement pattern generator 116 to generate the stripe pattern b1shown at upper right of FIG. 3 (Step S201). The stripe pattern b1 is afirst measurement pattern.

The stripe pattern generated by the measurement pattern generator 116 isoutputted as projection video of the projector 101 from the video inputunit 110 through the video processor 111, the distortion corrector 112,and the optical system 113. At this time, the distortion corrector 112is in an initial state in which distortion correction is not carriedout.

When a photographing instruction is outputted from the CPU 120 of thesmartphone 102 to the camera 122, video of the stripe pattern projectedfrom the projector 101 to a projection target is photographed (StepS202). The video photographed by the camera 122 is stored in the memory121.

The CPU 120 confirms whether all of the stripe patterns have alreadybeen photographed by the camera 122 or not (Step S203). In a case whereit is confirmed that all of the stripe patterns have not beenphotographed yet, the processing flow returns to the process at StepS201, and the measurement pattern generator 116 switches a next stripepattern.

The processes at Steps S201 to S203 repeat until all of the stripepatterns, that is, all of the stripe patterns b1 to b4 shown in FIG. 3and the stripe patterns f1 to f3 shown in FIG. 4 are photographed. Then,when all of the stripe patterns are photographed, the processing flowshifts to a next process at Step S204.

In a case where it is determined in the process at Step S203 that all ofthe stripe patterns are photographed, the CPU 120 of the smartphone 102executes correction of a video reference position for video of each of aplurality of stripe patterns photographed in the processes at Steps S201to S203 (Step S204).

<Example of Correcting Process for Video Reference Position>

Here, a correcting process for the video reference position will bedescribed.

FIG. 6 is an explanatory drawing showing one example of correction ofthe video reference position, which is the process at Step S204 in FIG.5.

FIG. 6(a) shows video obtained by photographing the stripe pattern b1shown in FIG. 3 in the process at Step S202 in FIG. 5. Similarly, FIG.6(b) shows video obtained by photographing the stripe pattern b2 shownin FIG. 3 in the process at Step S202 in FIG. 5.

Since the operator holds the smartphone 102 by his or her hands asdescribed above, a position of photographed video of each of the stripepatterns may shift to each other slightly as shown in FIG. 6(a) and FIG.6(b). FIG. 6(b) shows a state where the photographed video of the stripepattern b2 shifts with respect to the position of the photographed videoof the stripe pattern b1, which is shown by a dotted line.

In correction of the video reference position that is the process atStep S204, a position of the photographed video with the stripe patternshown in FIG. 6(b) is corrected on the basis of the position of thephotographed video shown in FIG. 6(a) so that the video of the stripepattern b1 overlaps with the video of the stripe pattern b2. FIG. 6(c)shows a state after the videos of the stripe patterns b1, b2 arecorrected.

As described above, the CPU 120 executes this process with respect toall kinds of the photographed video stored in the memory 121.Specifically, it is realized by extracting a periphery of the video fromthe common pattern region 131 formed in the stripe pattern, and addingcorrection thereto so that a peripheral position of the video is thesame as that of the photographed video shown in FIG. 6(a).

As described above, in the detecting process for the periphery of thevideo, it is possible to increase a difference of brightness between aregion in which no video is projected and a boundary of a peripheralregion of the video projected by the projector 101 by causing the videoin the common pattern region 131 to be high luminance. For this reason,it is possible to facilitate the detecting process for a peripheralportion of the projection video.

Here, the process at Step S204 in FIG. 5 is executed by the CPU 120.However, the process at Step S204 may be executed by the microcomputer114 of the projector 101, for example.

In that case, the video with the stripe pattern, which is photographedin the process at Step S202 in FIG. 5, is transmitted to themicrocomputer 114 whenever the video is photographed by the camera 122of the smartphone 102, and is stored in the memory 115, for example.

Subsequently, when correction of the video reference position, which isthe process at Step S204, is terminated in FIG. 5, the CPU 120 of thesmartphone 102 calculates distortion of each region of the video (StepS205), and calculates the distortion correction coefficient to correctdistortion of the projection video of the projector 101.

FIG. 7 is an explanatory drawing showing one example of the process atStep S205 in FIG. 5.

In order to calculate distortion for each region, a correction region isfirst determined. This correction region is determined by a boundarybetween the region 132 with black or low luminance and the region 133with white or high luminance. In a case where the four stripe patternsin the vertical direction shown in FIG. 3 and the three stripe patternsin the horizontal direction shown in FIG. 4 are used, as shown by dottedlines of FIG. 7, the video in the horizontal direction is divided intoeight regions, and the video in the vertical direction is divided intofour regions. This causes the video to be divided into 32 correctionregions.

<Example of Dividing Process for Correction Region>

This dividing process for the correction region will be described.

FIG. 8 is an explanatory drawing showing one example of the process ofdividing the correction region shown in FIG. 7.

A stripe pattern b2 shown at the uppermost of FIG. 8 is the same as thestripe pattern b2 shown in FIG. 3. There is a boundary between light anddark in the horizontal direction at a central portion of the screen inthe stripe pattern b2. A result when to detect a boundary position ofthis stripe pattern b2 is a detected result E1 shown under the stripepattern b2.

As stated above, the change in the luminance level may occur on theboundary in the stripe pattern. Thus, for example, by carrying out ahighpass filtering process for the video signal to convert it intoabsolute values, it is possible to obtain the detected result E1.Similarly, detected results E2, E3 respectively indicate results when todetect boundaries from the stripe pattern b3 and the stripe pattern b4shown in FIG. 3.

A detected result E4 is obtained by superposing the boundaries of thesedetected results E1 to E3. In this case, as shown in the detected resultE4, the video divided into eight regions in the horizontal direction isobtained. The distortion correction for each region is executed by usingthese divided regions of the detected result E4 as video correctionregions.

Similarly, the video divided into four regions in the vertical directionis obtained by using the stripe patterns f1 to f3 shown in FIG. 4.Herewith, the video is divided into 32 correction regions.

Here, explanation returns to FIG. 7. FIG. 7 (a) shows video with thepattern divided into the 32 regions as described above. FIG. 7(b) showsan example of the video with the 32-divided pattern formed byphotographing the video projected from the projector 101 as shown inFIG. 7(a) by means of the smartphone 102.

In the example of FIG. 7(b), the case where a projection plane to whichthe video is projected from the projector 101 is not flat and the centerthereof becomes hollow is shown. In this case, coordinates p11, p12,p21, p22 are respectively assigned to intersection points of the regionsof the video shown in FIG. 7(a).

In the case of FIG. 7(b), since the projection plane is not flat asdescribed above, the coordinates p11, p12, p21, p22 shown in FIG. 7(a)respectively correspond to distorted positions.

Thus, in order to correct the distortion shown in FIG. 7 (b) and deformthe projection video to a rectangule, correction is applied on the basisof the coordinates of the respective regions. For example, by applyingdistortion correction shown in FIG. 7 (d) to the distortion shown inFIG. 7(b) to correct the same, it is possible to obtain rectangularvideo after correction shown in FIG. 7(e).

This process includes: first seeking a rectangular region, that becomesthe maximum area shown in FIG. 7(c), from displayed video shown in FIG.7(b); and generating a distortion correction coefficient so as to fallwithin this range. This makes it possible to obtain the display videoshown in FIG. 7(e).

In such a case, the rectangular region described above is not always thesame aspect ratio as that of the original video depending upon a shapeof the projection plane. Thus, the distortion correction coefficient maybe obtained so as to become the whole rectangular region, and the videomay be displayed by changing the aspect ratio of the video.Alternatively, the distortion correction coefficient may be set so as tomaintain the aspect ratio of the video. Each of the processes describedabove is also executed by the CPU 120 of the smartphone 102. Asdescribed above, the process at Step S205 is terminated.

Here, the CPU 120 of the smartphone 102 also executes the process atStep S205. However, the microcomputer 114 of the projector 101 mayexecute the process at Step S205.

This makes it possible to reduce a load on the CPU 120 of the smartphone102. Therefore, it becomes possible to reduce power consumption of thesmartphone 102, whereby an effect to reduce consumption of a battery ofthe smartphone 102 can be obtained. In a case where the microcomputer114 of the projector 101 executes the process at Step S204 in FIG. 5described above, it is also possible to achieve the similar effect.

Subsequently, in FIG. 5, the smartphone 102 transmits the distortioncorrection coefficient calculated in the process at Step S205, which isa distortion correction parameter, to the projector 101 via the wirelesstransceiver 124 (Step S206). The projector 101 sets the distortioncorrection coefficient to the distortion corrector 112 via the wirelesstransceiver 117 and the microcomputer 114.

When the distortion correction coefficient is set to the distortioncorrector 112, the microcomputer 114 switches video to be taken in thevideo input unit 110 to inputted video (Step S207).

The setting process for the distortion correction is terminated by theseprocesses.

As described above, it is possible to reduce an influence such as camerashake at the time of photographing a stripe pattern that is ameasurement pattern. As a result, it is possible to carry out correctionof video with high accuracy.

Further, it is possible to require no tool to fix the smartphone, suchas a tripod, when the stripe pattern is photographed. Therefore, it ispossible to improve convenience.

Second Embodiment

<Outline>

In the first embodiment, as shown in FIG. 3, the common pattern region131 has been used as a pattern indicating a periphery of the entirevideo. However, there is the case where a common pattern region is to bechanged depending upon presence or absence of each of a shape, color, apattern of a projection plane. In a second embodiment, another exampleof the common pattern region 131 will be described.

<Example of Common Pattern Region>

FIG. 9 is an explanatory drawing showing one example of the commonpattern region that is formed in the stripe pattern according to thesecond embodiment.

A stripe pattern a2 shown at the uppermost of FIG. 9 shows a stripepattern before a common pattern region is added thereto, and is the sameas the stripe pattern a2 shown in FIG. 3 according to the firstembodiment.

Stripe patterns e2 a, e 2 b, e 2 c shown under the stripe pattern a2respectively show new examples in each of which a common pattern region131 is provided in the stripe pattern a2.

The stripe pattern e2 a is similar to the stripe pattern b2 shown inFIG. 3, and a common pattern region 131 is provided on a periphery ofvideo in the stripe pattern e2 a. The stripe pattern e2 b under thestripe pattern e2 a show an example in which a common pattern region 131is not provided on the periphery of the video, but is provided at aposition of 75% of each of vertical and horizontal lengths with respectto the center of the video, for example.

Further, the stripe pattern e2 c shown under the stripe pattern e2 bshows an example in which a common pattern region 131 is provided at aposition of 50% of each of vertical and horizontal lengths with respectto the center of the video, for example.

For example, depending upon the shape of the projection plane, a blindarea when viewed from the camera 122 shown in FIG. 2 may occur whenprojected video is photographed. In that case, a user switches commonpattern regions so as to become the optimum position, whereby it ispossible to set the distortion correction while avoiding any blind areaof the video due to a position of the camera 122.

If it can be known at which position on a screen the common patternregion 131 exists, it is possible to calculate the distortion correctioncoefficient that has been explained in the first embodiment. Thisswitching of the common pattern region 131 may be executed by anapplication or the like of the smartphone 102 in FIG. 1, which has beenexplained in the first embodiment, for example, and may be executed atthe time of start of a distortion correcting process.

<Example of Setting Process for Distortion Correction Coefficient>

FIG. 10 is a flowchart showing one example of a setting process for adistortion correction coefficient, which includes the switching processfor the common pattern region 131 shown in FIG. 9.

In the case of a setting process by the flowchart show in FIG. 10, aprocess at Step S208 is newly added thereto with respect to theflowchart shown in FIG. 5 according to the first embodiment. Note thathardware is the same configuration shown in FIG. 2.

This process at Step S208 is added to the setting process for thedistortion correction coefficient as a first step. First, when a patternof the stripe pattern e2 a shown in FIG. 9 is displayed, the userconfirms the screen of the smartphone 102 to confirm whether the entirevideo is included in a photographing range or not.

Here, in a case where the video of the projector 101 lacks due to theblind area described above or the like, the user carries out a switchingoperation for the common pattern region 131 so that the common patternregion 131 does not lack (Step S208).

This operation allows the user to set distortion correction in which anyblind area is avoided. Note that the processes after Step S208, that is,the processes at Steps S201 to S207 in FIG. 10 are similar to theprocesses at Steps S201 to S207 in FIG. 5. Therefore, its explanation isomitted.

In the explanation described above, one example has been shown in whichany one is selected, as the position of the common pattern region 131,from three stages of the periphery of the video, which include theposition of 75% of each of the vertical and horizontal lengths withrespect to the center of the video, and the position of 50% of each ofthe vertical and horizontal lengths with respect to the center of thevideo. However, the position of the common pattern region 131 is notlimited to these examples, the position may be switched by a finerinterval.

Further, the case where the user carries out the confirmation of thephotographing range of the common pattern region 131 and the switchingoperation has been described in FIG. 10. However, the CPU 120 of thesmartphone 102 may determine whether the common pattern region 131 isincluded in the photographing range or not and whether a video regioncan be discriminated or not. In the determination of whether the videoregion can be discriminated or not, the CPU 120 determines a luminancelevel or color level of the common pattern region 131, and determinesthat the video region cannot be discriminated in a case where any levelis not more than a threshold value set in advance, for example.

Then, in a case where the video region cannot be discriminated, forexample, an alert may be outputted. The alert is an alarm and display bywhich the user is encouraged to switch, for example. The display bywhich the user is encouraged to switch allows the user to select asuitable stripe pattern and a suitable common pattern region.

Moreover, in addition to this, the CPU 120 of the smartphone 102automatically executes the switching of common pattern regions, wherebyit is possible to further improve usability of the user. In this case,when the alert is to be outputted, the CPU 120 transmits, to themeasurement pattern generator 116 through the wireless transceivers 124,117, a control signal to change at least any one of the luminance, thecolor, or the position of the common pattern region 131. The measurementpattern generator 116 that receives this control signal changes at leastany one of the luminance, the color, or the position of the commonpattern region 131.

As described above, it is possible to reduce a lack (or failure) of thecommon pattern region 131 caused by the shape of the projection plane.Therefore, it is possible to execute distortion correction with higheraccuracy.

Third Embodiment

<Outline>

In the first and second embodiments, the example in which the commonpattern region is provided in a picture frame manner has been described.However, in a third embodiment, another example of a shape of a commonpattern region 131 will be described.

<Example of Common Pattern Region>

FIG. 11 is an explanatory drawing showing one example of a commonpattern region formed in a stripe pattern according to the thirdembodiment.

A stripe pattern a2 shown at the uppermost of FIG. 11 is the same as thestripe pattern a2 shown in FIG. 3 according to the first embodiment.Stripe patterns d2 a to d 2 c shown under the stripe pattern a2respectively show new examples in each of which common pattern regions131 are provided in the stripe pattern a2.

In the case of the stripe pattern d2 a, a common pattern region 131 isprovided at each of positions of four corners on the right, left, topand bottom of video. Each of the common pattern regions 131 isconfigured by a punctiform quadrangle. Further, in the stripe pattern d2b shown under the stripe pattern d2 a, the common pattern regions 131,each of which is configured by the punctiform quadrangle, arerespectively provided at corresponding positions of 75% of each ofvertical and horizontal lengths with respect to the center of the video.

In the striper pattern d2 c shown under the stripe pattern d2 b, thecommon pattern regions 131, each of which is configured by thepunctiform quadrangle, are respectively provided at correspondingpositions of 50% of each of vertical and horizontal lengths with respectto the center of the video.

In this case, a user is allowed to select any of the stripe patterns d2a to d 2 c in view of the blind area of the camera 122 shown in FIG. 2to carry out setting of distortion correction as well as the examplethat has been explained in the second embodiment.

Further, color of the common pattern region 131 may be changed inaddition to luminance. Moreover, the common pattern region 131 may beconfigured so that color thereof can be selected. By allowing the colorto be selected, it is possible to discriminate regions by not only usinga level difference in luminance between a common pattern region in videophotographed when the video is projected to a projection plane withcolor and the other region, but also using a level difference in colorthereof. This makes it possible to improve detection accuracy ofdistortion.

<Example of Screen Display>

FIG. 12 is an explanatory drawing showing one example of screen displaywhen the common pattern regions shown in FIG. 11 are switched. Here, thesmartphone 102 has the similar configuration to that shown in FIG. 2.

As shown in FIG. 12, an application screen to set distortion correctiondescribed above is displayed on a display 123. In the display on thedisplay 123, there is a display region 502 for displaying videophotographed by a built-in camera at an upper portion of the display123.

A zoom button 503 for a camera 122 is displayed at a lower left portionof the display region 502. A pattern switching button 504 for switchingdisplay of the common pattern region 131 is displayed at a right side ofthe zoom button 503.

Further, a start button 505 to start setting of distortion correction isdisplayed at a right side of the pattern switching button 504. Thepattern switching button 504 described above may be configured so as toinclude a plurality of button displays such as “size switching”,“luminance switching”, “color switching”, or “auto”, that is, a menu,for example.

As described above, it is possible to switch a size, luminance, or colorof the common pattern region 131. Therefore, it becomes possible tocause the user to recognize the common pattern region 131 successfully,and this makes it possible to improve detection accuracy of distortion.

In this regard, the present invention is not limited to the embodimentsdescribed above, and various modifications are contained. For example,the embodiments described above have been explained in detail forexplaining the present invention clearly. The present invention is notnecessarily limited to one that includes all configurations that havebeen explained.

Further, a part of the configuration of one embodiment can be replacedby a configuration of the other embodiment. Further, a configuration ofthe other embodiment can be added to a configuration of one embodiment.Moreover, a part of the configuration of each of the embodiments can beadded to the other configuration, deleted or replaced thereby.

REFERENCE SINGS LIST

-   101 projector-   102 smartphone-   103 screen-   110 video input unit-   111 video processor-   112 distortion corrector-   113 optical system-   114 microcomputer-   115 memory-   116 the measurement pattern generator-   117 wireless transceiver-   121 memory-   122 camera-   123 display-   124 wireless transceiver-   131 common pattern region

1. A projection apparatus comprising: a projector configured to projecta plurality of measurement patterns generated by a measurement patterngenerator; a transceiver configured to communicate with an externalmobile terminal to receive information regarding distortion correctionfor a video to be projected by the projector from the external mobileterminal; and a distortion corrector configured to correct distortion ofthe video to be projected by the projector on a basis of the informationregarding the distortion correction received from the external mobileterminal, wherein the measurement pattern generator is configured to adda common pattern to each of the plurality of measurement patterns, thecommon pattern indicating a reference position of each of themeasurement patterns, and wherein the information regarding thedistortion correction received from the external mobile terminal isgenerated by the external mobile terminal based on the plurality ofmeasurement patterns, to which the common pattern is added, and whichare photographed by a camera of the external mobile terminal.
 2. Theprojection apparatus according to claim 1, wherein the plurality ofmeasurement patterns generated by the measurement pattern generatorincludes a stripe pattern.
 3. The projection apparatus according toclaim 1, wherein the common pattern added to the plurality ofmeasurement patterns is a periphery of an entire of the video to beprojected by the projector.
 4. The projection apparatus according toclaim 1, wherein the common pattern added to the plurality ofmeasurement patterns is a rectangular shape pattern smaller than anentire of the video to be projected by the projector.
 5. The projectionapparatus according to claim 1, wherein the common pattern added to theplurality of measurement patterns is a set of four points each of whichis located a corner of an entire of the video to be projected by theprojector.
 6. The projection apparatus according to claim 1, wherein thecommon pattern added to the plurality of measurement patterns is a setof four points each of which is located a corner of a rectangularsmaller than an entire of the video to be projected by the projector. 7.The projection apparatus according to claim 2, wherein the commonpattern added to the plurality of measurement patterns is a periphery ofan entire of the video to be projected by the projector.
 8. Theprojection apparatus according to claim 2, wherein the common patternadded to the plurality of measurement patterns is a rectangular shapepattern smaller than an entire of the video to be projected by theprojector.
 9. The projection apparatus according to claim 2, wherein thecommon pattern added to the plurality of measurement patterns is a setof four points each of which located a corner of an entire of the videoto be projected by the projector.
 10. The projection apparatus accordingto claim 2, wherein the common pattern added to the plurality ofmeasurement patterns is a set of four points each of which located acorner of a rectangular smaller than an entire of the video to beprojected by the projector.